GEMPACK USER DOCUMENTATION Release 7.0 GPD-3 Simulation Reference : GEMSIM, TABLO-generated Programs and SAGEM Simulation Reference : GEMSIM, TABLO-generated Programs and SAGEM GEMPACK Document No. GPD-3 W. J. Harrison K. R. Pearson Centre of Policy Studies and Impact Project Monash University, Melbourne, Australia First edition October 2000 Copyright 1985-2000. The Impact Project and KPSOFT. First edition October 2000 ISSN 1030-2514 ISBN 0-7326-1522-4 This is part of the documentation of the GEMPACK Software System for solving large economic models, developed by the IMPACT Project, Monash University, Clayton Vic 3800, Australia. Abstract GEMPACK is a suite of general-purpose economic modelling software especially suitable for applied general equilibrium models. GEMPACK provides software for calculating accurate solutions of an economic model, starting from an algebraic representation of the model. Simulations to solve for the endogenous variables given the exogenous variables and the shocks to these variables, are run in GEMPACK using one of the following programs: • the program GEMSIM, • the TABLO-generated program written by TABLO from the TABLO Input file for the model, or • the program SAGEM. This document is a complete reference for running simulations. Details are given of the syntax used in Command files and the methods used in solving the equations of the model. We assume that you are familiar with GEMPACK document GPD-1 An Introduction to GEMPACK. Document Attributes Name : Simulation Reference : GEMSIM, TABLO-generated Programs and SAGEM Audience : CGE Modellers Identifier : GPD-3 History : Date Author(s) Comment October 2000 Jill Harrison and Ken Pearson First Edition (Release 7.0) In the Release 6.0 documentation, GEMPACK document GPD-3 was “How to Create and Modify GEMPACK Header Array Files Using the Program MODHAR”. This material is now in Chapter 3 of GPD-4. Table of Contents 1. INTRODUCTION 1-1 2. COMMAND FILES 2-3 2.1 Simulations using GEMSIM or TABLO-generated Programs 2-3 2.2 Data Manipulation using GEMSIM or TABLO-generated Programs 2-4 2.3 SAGEM Simulations 2-5 2.4 Naming the Command file 2-5 2.4.1 File Names Containing Spaces 2-5 2.5 Using the Command File Stem for Names of Other Output Files 2-6 2.5.1 Default: Solution file stem = Command file stem 2-7 2.5.2 Default: Log file stem = Command file stem 2-7 2.5.3 Default: Display file stem = Command file stem 2-7 2.5.4 Using <Cmf> in Command files 2-7 2.6 Log Files and Reporting CPU Time 2-8 2.7 General Points about Command File Statements 2-8 2.8 Eliminating Syntax Errors in GEMPACK Command Files 2-10 3. TABLO INPUT FILES AND AUXILIARY FILES 3-11 3.1 GEMSIM and GEMSIM Auxiliary Files 3-11 3.2 TABLO-generated Programs and Auxiliary Files 3-11 3.3 How are the Names of the Auxiliary Files Determined? 3-12 3.4 Check that Auxiliary Files are Correct 3-13 3.4.1 Compatibility of Various Files 3-13 3.5 Carrying out Simulations on Other Machines 3-13 3.5.1 GEMPACK Licence May Be Required 3-14 4. DATA FILES, UPDATED DATA FILES AND DISPLAY FILES 4-15 4.1 Data Files and Logical Files 4-15 4.1.1 Input and Output Data files 4-16 4.2 Updated Data Files 4-17 4.2.1 Naming Updated Files 4-17 4.2.2 Updated Data Read from the Terminal 4-17 4.2.3 Intermediate Data Files 4-18 4.3 Display Files 4-18 4.3.1 Options for Display Files 4-18 i 4.4 Checking Set and Element Information when Reading Data 4-19 4.4.1 Check-on-Read Problems with RunGEM, RunDynam and RunMONASH 4-21 4.4.2 Checks When Reading Set Element Names from a File 4-21 4.5 Names of Intermediate Data Files 4-22 4.5.1 Default Names for Intermediate Files When Using a Command File 4-23 5. CHOOSING THE CLOSURE AND SHOCKS 5-25 5.1 Specifying the Closure 5-25 5.1.1 Miniature ORANI Model 5-25 5.2 Specifying the Closure via a Command File 5-27 5.2.1 Specifying the Closure from Scratch 5-27 5.2.2 Using a Saved Closure 5-28 5.2.3 Modifying a Saved Closure 5-29 5.2.4 Closure Specified Using Data Files 5-29 5.2.5 List of Exogenous/Endogenous Variables when Closure is Invalid 5-30 5.3 Component Numbers for a Variable 5-30 5.3.1 Examples of Component Numbers 5-30 5.4 Choosing Other Sets of Variables 5-31 5.4.1 Choosing Sets of Variables via a Command File 5-31 5.4.2 Example of Choosing Sets in SAGEM 5-33 5.4.3 Choosing Sets of Variables Interactively 5-34 5.5 Specifying the Shocks 5-35 5.5.1 Specifying the Shocks via a Command File 5-35 5.5.2 Using a Shock File 5-36 5.5.3 Reading Shocks from Header Array file 5-36 5.5.4 Shocking a Variable with No Components Exogenous 5-36 5.5.5 Additional and Target Shock (ashock or tshock) Statements for Dynamic Models 5-37 5.6 Clarification Concerning Shocks on a Command File 5-38 5.6.1 Shock Statement when only Some Components are Exogenous 5-38 5.6.2 No “Shock” Statements on a Command File 5-38 5.7 Specifying the Shocks Interactively 5-39 5.8 Shock File Syntax 5-40 5.9 Checking the Closure and Shocks 5-41 6. ACTIONS IN GEMSIM AND TABLO-GENERATED PROGRAMS 6-43 6.1 Possible Actions in GEMSIM and TABLO-generated Programs 6-43 6.1.1 Multi-Step Simulations with Economic Models 6-43 6.1.2 Creating an Equations File 6-43 6.1.3 Other Actions (Writes, Displays, Assertions, Range Tests and Transfers) 6-44 6.1.4 Data Manipulation 6-44 6.1.5 “Extra” (TABLO-like) Actions 6-45 6.1.6 Checking the Closure and Shocks 6-45 6.1.7 Controlling Whether and How the Actions are Carried Out 6-45 6.1.8 Some READs and FORMULAS May be Omitted 6-45 6.1.9 Writes and Displays at all Steps of a Multi-step Simulation 6-46 6.1.10 Echoing Activity 6-46 6.1.11 Writes to the Terminal 6-46 ii 6.2 How These Programs Carry Out Multi-step Simulations 6-47 6.2.1 Processing the Closure and Shocks in GEMSIM or TABLO-generated Programs 6-49 6.2.2 Results of a 4-step Simulation Looked at in Detail 6-50 6.3 Assertions 6-51 6.4 Range Tests 6-52 6.4.1 How to Specify the Allowed Range for Values of a Coefficient or Levels Variable 6-53 6.4.2 Tests Carried Out 6-54 6.4.3 An Example 6-54 6.4.4 Associated Statements in Command Files 6-55 6.5 Transfer Statements 6-56 6.6 TABLO-like Statements in Command Files 6-56 6.6.1 TABLO-Like Checks of Extra Statements 6-57 6.6.2 Qualifiers 6-57 6.6.3 Other Points 6-57 6.7 Coefficients May Not Be Fully Initialised 6-58 7. MULTI-STEP SOLUTION METHODS 7-59 7.1 Command File Statements for Method and Steps 7-59 7.2 Extrapolation Accuracy Summaries for Data and for Levels Variables 7-60 7.2.1 For Data 7-60 7.2.2 For Levels Variables 7-60 7.2.3 Command File Statements Affecting Extrapolation Accuracy Summaries and Files 7-61 7.3 Splitting a Simulation into Several Subintervals 7-62 7.3.1 Advantages of Using Several Subintervals 7-64 7.4 User-specified Accuracy for Simulations 7-64 7.4.1 Specifying Which Solutions to Use 7-65 7.4.2 Incompatibilities 7-65 7.4.3 Automatic Accuracy with Models which Read Data from the Terminal 7-66 7.4.4 Adaptive Stepsize Method 7-66 7.4.5 Stopping if Subintervals Become Too Small 7-66 7.4.6 Controlling Which Values are Tested 7-66 7.5 Newton’s Method for Levels Models 7-67 7.5.1 Newton’s Method and ORANIF 7-67 7.5.2 Convergence 7-68 7.5.3 General advice 7-68 7.5.4 Newton’s Method Is Not Reliable with Mixed Models 7-68 7.6 Options for Saving Solution and Updated Data Files 7-69 7.6.1 Saving Solutions or Updated Data After Separate Multi-step Calculations 7-69 7.6.2 Saving Updated Values from All FORMULA(INITIAL)s 7-69 8. SOLUTION FILES 8-71 8.1 Command File Statements Related to Solution files 8-71 8.1.1 SAGEM Only Command File Statements 8-72 8.2 Contents of Solution Files 8-72 8.2.1 TABLO File and TABLO STI File Stored on Solution File 8-73 iii 8.2.2 Command File Stored on Solution file 8-73 8.3 Levels Results 8-73 8.4 Solution Coefficients (SLC) Files 8-74 8.4.1 Solution and SLC Files are Complete Record of the Simulation 8-74 9. EQUATIONS FILES AND BASE COEFFICIENT VALUES (BCV) FILES 9-75 9.1 Equations Files 9-75 9.1.1 Using an Equations file in SAGEM 9-75 9.1.2 Differences in Step 1 Depending on Whether or Not Equations File is Saved 9-75 9.1.3 Model Name, Version and Identifier 9-76 9.2 Base Coefficient Values (BCV) Files 9-77 9.2.1 Starting from Existing Equations and BCV Files Not Recommended 9-77 10.